1. Field of the Invention
The present invention relates to an image display apparatus.
2. Description of the Related Art
In recent years, image display apparatus such as color liquid crystal display apparatus or the like, for example, have been demanded to handle increased electric power consumption due to their higher performance capability. In particular, color liquid crystal display apparatus, for example, have backlights that consume more electric power because of their trends for higher definition, wider color reproduction range, and higher luminance. To solve the problem, attention has been drawn to a technology for constructing each display pixel of four auxiliary pixels which include a white display auxiliary pixel for displaying white color, for example, in addition to a red display auxiliary pixel for displaying red color, a green display auxiliary pixel for displaying green color, and a blue display auxiliary pixel for displaying blue color, the white display auxiliary pixel being used to increase luminance. Since the four auxiliary pixel configuration can produce higher luminance with the same electric power consumed as heretofore, if the same luminance is to be achieved as heretofore, then it is possible to reduce the electric power consumed by the backlight, and to increase the quality of displayed images.
Japanese patent No. 3167026, for example, discloses a color image display apparatus including:
means for generating three types of color signals according to an additive three-primary process from an input signal; and
means for generating an auxiliary signal by adding the color signals of three hues at identical ratios and supplying four types of display signals which include the auxiliary signal and three types of color signals produced by subtracting the auxiliary signal from the color signals of three hues to a display unit. The three types of color signals drive red, green, and blue display auxiliary pixels, and the auxiliary signal drives white display auxiliary pixels.
There are known in the art image display apparatus which employ a color filter free of a black matrix (hereinafter referred to as “black-matrix-less color filter” for descriptive purposes). Since no black matrix is included, the image display apparatus have a high aperture ratio (high transmittance). The image display apparatus include light shielding areas as an alternative to a black matrix, which are provided by superposing a corresponding color filter layer on adjacent auxiliary pixels.